/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 * 
 *      http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.tencent.wepay.helper;

import java.util.Properties;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

// Contributors:   Avy Sharell (sharell@online.fr)
//                 Matthieu Verbert (mve@zurich.ibm.com)
//                 Colin Sampaleanu

/**
 * A convenience class to convert property values to specific types.
 * 
 * @author Ceki G&uuml;lc&uuml;
 * @author Simon Kitching;
 * @author Anders Kristensen
 */
public class OptionConverter {
	private static Logger logger = LoggerFactory
			.getLogger(OptionConverter.class);
	static String DELIM_START = "${";
	static char DELIM_STOP = '}';
	static int DELIM_START_LEN = 2;
	static int DELIM_STOP_LEN = 1;

	/** OptionConverter is a static class. */
	private OptionConverter() {
	}

	public static String[] concatanateArrays(String[] l, String[] r) {
		int len = l.length + r.length;
		String[] a = new String[len];

		System.arraycopy(l, 0, a, 0, l.length);
		System.arraycopy(r, 0, a, l.length, r.length);

		return a;
	}

	public static String convertSpecialChars(String s) {
		char c;
		int len = s.length();
		StringBuffer sbuf = new StringBuffer(len);

		int i = 0;
		while (i < len) {
			c = s.charAt(i++);
			if (c == '\\') {
				c = s.charAt(i++);
				if (c == 'n')
					c = '\n';
				else if (c == 'r')
					c = '\r';
				else if (c == 't')
					c = '\t';
				else if (c == 'f')
					c = '\f';
				else if (c == '\b')
					c = '\b';
				else if (c == '\"')
					c = '\"';
				else if (c == '\'')
					c = '\'';
				else if (c == '\\')
					c = '\\';
			}
			sbuf.append(c);
		}
		return sbuf.toString();
	}

	/**
	 * Very similar to <code>System.getProperty</code> except that the
	 * {@link SecurityException} is hidden.
	 * 
	 * @param key
	 *            The key to search for.
	 * @param def
	 *            The default value to return.
	 * @return the string value of the system property, or the default value if
	 *         there is no property with that key.
	 * @since 1.1
	 */
	public static String getSystemProperty(String key, String def) {
		try {
			return System.getProperty(key, def);
		} catch (Throwable e) { // MS-Java throws
								// com.ms.security.SecurityExceptionEx
			logger.debug("Was not allowed to read system property \"" + key
					+ "\".");
			return def;
		}
	}

	public static Object instantiateByKey(Properties props, String key,
			Class superClass, Object defaultValue) {

		// Get the value of the property in string form
		String className = findAndSubst(key, props);
		if (className == null) {
			logger.error("Could not find value for key " + key);
			return defaultValue;
		}
		// Trim className to avoid trailing spaces that cause problems.
		return OptionConverter.instantiateByClassName(className.trim(),
				superClass, defaultValue);
	}

	/**
	 * If <code>value</code> is "true", then <code>true</code> is returned. If
	 * <code>value</code> is "false", then <code>true</code> is returned.
	 * Otherwise, <code>default</code> is returned.
	 * 
	 * <p>
	 * Case of value is unimportant.
	 */
	public static boolean toBoolean(String value, boolean dEfault) {
		if (value == null)
			return dEfault;
		String trimmedVal = value.trim();
		if ("true".equalsIgnoreCase(trimmedVal))
			return true;
		if ("false".equalsIgnoreCase(trimmedVal))
			return false;
		return dEfault;
	}

	public static int toInt(String value, int dEfault) {
		if (value != null) {
			String s = value.trim();
			try {
				return Integer.valueOf(s).intValue();
			} catch (NumberFormatException e) {
				logger.error("[" + s + "] is not in proper int form.");
				e.printStackTrace();
			}
		}
		return dEfault;
	}

	public static long toFileSize(String value, long dEfault) {
		if (value == null)
			return dEfault;

		String s = value.trim().toUpperCase();
		long multiplier = 1;
		int index;

		if ((index = s.indexOf("KB")) != -1) {
			multiplier = 1024;
			s = s.substring(0, index);
		} else if ((index = s.indexOf("MB")) != -1) {
			multiplier = 1024 * 1024;
			s = s.substring(0, index);
		} else if ((index = s.indexOf("GB")) != -1) {
			multiplier = 1024 * 1024 * 1024;
			s = s.substring(0, index);
		}
		if (s != null) {
			try {
				return Long.valueOf(s).longValue() * multiplier;
			} catch (NumberFormatException e) {
				logger.error("[" + s + "] is not in proper int form.");
				logger.error("[" + value + "] not in expected format.", e);
			}
		}
		return dEfault;
	}

	/**
	 * Find the value corresponding to <code>key</code> in <code>props</code>.
	 * Then perform variable substitution on the found value.
	 */
	public static String findAndSubst(String key, Properties props) {
		String value = props.getProperty(key);
		if (value == null)
			return null;

		try {
			return substVars(value, props);
		} catch (IllegalArgumentException e) {
			logger.error("Bad option value [" + value + "].", e);
			return value;
		}
	}

	/**
	 * Instantiate an object given a class name. Check that the
	 * <code>className</code> is a subclass of <code>superClass</code>. If that
	 * test fails or the object could not be instantiated, then
	 * <code>defaultValue</code> is returned.
	 * 
	 * @param className
	 *            The fully qualified class name of the object to instantiate.
	 * @param superClass
	 *            The class to which the new object should belong.
	 * @param defaultValue
	 *            The object to return in case of non-fulfillment
	 */
	public static Object instantiateByClassName(String className,
			Class superClass, Object defaultValue) {
		if (className != null) {
			try {
				Class classObj = Loader.loadClass(className);
				if (!superClass.isAssignableFrom(classObj)) {
					logger.error("A \"" + className
							+ "\" object is not assignable to a \""
							+ superClass.getName() + "\" variable.");
					logger.error("The class \"" + superClass.getName()
							+ "\" was loaded by ");
					logger.error("[" + superClass.getClassLoader()
							+ "] whereas object of type ");
					logger.error("\"" + classObj.getName()
							+ "\" was loaded by [" + classObj.getClassLoader()
							+ "].");
					return defaultValue;
				}
				return classObj.newInstance();
			} catch (ClassNotFoundException e) {
				logger.error(
						"Could not instantiate class [" + className + "].", e);
			} catch (IllegalAccessException e) {
				logger.error(
						"Could not instantiate class [" + className + "].", e);
			} catch (InstantiationException e) {
				logger.error(
						"Could not instantiate class [" + className + "].", e);
			} catch (RuntimeException e) {
				logger.error(
						"Could not instantiate class [" + className + "].", e);
			}
		}
		return defaultValue;
	}

	/**
	 * Perform variable substitution in string <code>val</code> from the values
	 * of keys found in the system propeties.
	 * 
	 * <p>
	 * The variable substitution delimeters are <b>${</b> and <b>}</b>.
	 * 
	 * <p>
	 * For example, if the System properties contains "key=value", then the call
	 * 
	 * <pre>
	 * String s = OptionConverter.substituteVars(&quot;Value of key is ${key}.&quot;);
	 * </pre>
	 * 
	 * will set the variable <code>s</code> to "Value of key is value.".
	 * 
	 * <p>
	 * If no value could be found for the specified key, then the
	 * <code>props</code> parameter is searched, if the value could not be found
	 * there, then substitution defaults to the empty string.
	 * 
	 * <p>
	 * For example, if system propeties contains no value for the key
	 * "inexistentKey", then the call
	 * 
	 * <pre>
	 * String s = OptionConverter
	 * 		.subsVars(&quot;Value of inexistentKey is [${inexistentKey}]&quot;);
	 * </pre>
	 * 
	 * will set <code>s</code> to "Value of inexistentKey is []"
	 * 
	 * <p>
	 * An {@link java.lang.IllegalArgumentException} is thrown if
	 * <code>val</code> contains a start delimeter "${" which is not balanced by
	 * a stop delimeter "}".
	 * </p>
	 * 
	 * <p>
	 * <b>Author</b> Avy Sharell</a>
	 * </p>
	 * 
	 * @param val
	 *            The string on which variable substitution is performed.
	 * @throws IllegalArgumentException
	 *             if <code>val</code> is malformed.
	 */
	public static String substVars(String val, Properties props)
			throws IllegalArgumentException {

		StringBuffer sbuf = new StringBuffer();

		int i = 0;
		int j, k;

		while (true) {
			j = val.indexOf(DELIM_START, i);
			if (j == -1) {
				// no more variables
				if (i == 0) { // this is a simple string
					return val;
				} else { // add the tail string which contails no variables and
							// return the result.
					sbuf.append(val.substring(i, val.length()));
					return sbuf.toString();
				}
			} else {
				sbuf.append(val.substring(i, j));
				k = val.indexOf(DELIM_STOP, j);
				if (k == -1) {
					throw new IllegalArgumentException(
							'"'
									+ val
									+ "\" has no closing brace. Opening brace at position "
									+ j + '.');
				} else {
					j += DELIM_START_LEN;
					String key = val.substring(j, k);
					// first try in System properties
					String replacement = getSystemProperty(key, null);
					// then try props parameter
					if (replacement == null && props != null) {
						replacement = props.getProperty(key);
					}

					if (replacement != null) {
						// Do variable substitution on the replacement string
						// such that we can solve "Hello ${x2}" as "Hello p1"
						// the where the properties are
						// x1=p1
						// x2=${x1}
						String recursiveReplacement = substVars(replacement,
								props);
						sbuf.append(recursiveReplacement);
					}
					i = k + DELIM_STOP_LEN;
				}
			}
		}
	}
}
